docs: def _clean_tmp_dirs(self):
          """
          Remove temporary dir associated with this backend instance.
  
          :return: None
          """
  
          def onerror(fnc, path, excinfo):
              # we might not have rights to do this, the files could be owned by root
              self.logger.info("we were not able to remove temporary file %s: %s", path, excinfo[1])
  
          shutil.rmtree(self.tmpdir, onerror=onerror)
          self.tmpdir = None
          global _backend_tmpdir
          _backend_tmpdir = None